Add method punctuation handling to #synchronize

activesupport/lib/active_support/core_ext/module/synchronization.rb

@@ -19,13 +19,15 @@ class Module
     end
 
     methods.each do |method|
-      if instance_methods.include?("#{method}_without_synchronization")
+      aliased_method, punctuation = method.to_s.sub(/([?!=])$/, ''), $1
+      
+      if instance_methods.include?("#{aliased_method}_without_synchronization#{punctuation}")
         raise ArgumentError, "#{method} is already synchronized. Double synchronization is not currently supported."
       end
       module_eval(<<-EOS, __FILE__, __LINE__)
-        def #{method}_with_synchronization(*args, &block)
+        def #{aliased_method}_with_synchronization#{punctuation}(*args, &block)
           #{with}.synchronize do
-            #{method}_without_synchronization(*args,&block)
+            #{aliased_method}_without_synchronization#{punctuation}(*args,&block)
           end
         end
       EOS

activesupport/test/core_ext/module/synchronization_test.rb

@@ -54,4 +54,18 @@ class SynchronizationTest < Test::Unit::TestCase
     @instance.to_s
     assert_equal 2, dummy.sync_count
   end
+
+  def test_can_synchronize_method_with_punctuation
+    @target.module_eval do
+      def dangerous?
+        @dangerous
+      end
+      def dangerous!
+        @dangerous = true
+      end
+    end
+    @target.synchronize :dangerous?, :dangerous!, :with => :mutex
+    @instance.dangerous!
+    assert @instance.dangerous?
+  end
 end